clear all; clc; close all;

alpha_f = deg2rad(10);
beta_f = deg2rad(0);

alpha_s = deg2rad(-90:5:90);
beta_s = deg2rad(-180:5:180);

beta  = H(alpha_f, beta_f);
F = nan(length(alpha_s), length(beta_s));
for a = 1:length(alpha_s)
    for b = 1:length(beta_s)
        S=1;
        y=H(alpha_s(a), beta_s(b))*S;
        U=beta'*y;
        F(a,b)=abs(U/S)^2;
    end
end

[alpha_sm, beta_sm] = meshgrid(alpha_s, beta_s);

[Fx, Fy, Fz] = sph2cart(beta_sm, alpha_sm, F.');

figure;
surf(Fx, Fy, Fz)